Tracheal intubation is the placement of a tube in the trachea (windpipe) of a patient, which is necessary in many clinical situations to provide ventilation and oxygenation. For many decades, tracheal intubation has been performed under direct vision using a Macintosh laryngoscope, which has been considered the standard technique of intubation. Unfortunately, this approach to tracheal intubation has limitations. Intubation using this technique can be difficult and can, particularly in emergency situations, result in a high failure rate.
This has led to the development of alternative intubation devices and techniques using indirect vision, such as rigid and flexible endoscopes, video-laryngoscopes, and optical intubating stylets. Unfortunately, these devices are complex and expensive. Furthermore, in the presence of blood, secretions, and vomitus in the upper airway, as well as fogging of the lens or camera on the laryngoscope, it can be challenging to see the glottis (voice box) and the passage of the tracheal tube when employing the existing optical stylets and video scopes.
These difficulties have motivated the development of non-visual techniques, such as the light-guided intubation using a light-wand. The light-wand uses the principle of transillumination of the soft tissues of the neck, which was first described for nasotracheal intubation by Yamamura et al. in “M. K. Device for blind nasal intubation”, Anesthesiology 1959; 20:221. The light-wand consists of a malleable stylet with a light-bulb at the distal tip, and a power source. The lighted tip of the light-wand is mounted inside the distal end of the tracheal tube so that it can be guided into the trachea using the light-glow—transillumination—at the anterior surface of the neck, taking the advantage of the superficial location of the trachea relative to the esophagus—food passage. When the tip of the lighted tracheal tube enters the glottis, a well-defined circumscribed glow can be readily seen slightly below the Adam's apple—thyroid prominence—of the anterior neck, while only a diffuse glow is visible when the lighted tracheal tube is in the esophagus. Using this technique, the practitioner can guide the tip of the tracheal tube easily and safely into the trachea without seeing the glottis.
Throughout the 1970s and 1980s, various versions of light-wand devices have been developed. However during use of these devices over the years substantial drawbacks have been identified such as:
poor light intensity; deterioration of light intensity in reusable incandescent devices with repeated usage and sterilization;
loss of the incandescent light bulb into the trachea;
heat injury to the airway mucosa from the incandescent light bulb;
inadequate length, limiting the use of the light-wand device to a shorter or cut tracheal tube;
rigidity of the light-wand, hampering use of the devices for light-guided nasal intubation; and
inability of rigid light-wand devices to advance into the trachea beyond the glottis limiting their clinical utility to confirm correct tube placement into the trachea.
Some of these drawbacks have been overcome by the light-wand device disclosed in U.S. Pat. No. 5,163,841—and sold as TRACHLIGHT™ light-wand device—by providing an improved light source and added flexibility to the wand portion of the device. Unfortunately, the TRACHLIGHT™ light-wand device still has various drawbacks such as: use of an incandescent lightbulb having a fixed light intensity and generating a significant amount of heat; difficulties holding the trocar wire in place during oral intubation; deformation of the trocar wire with multiple use; and, absence of positive confirmation of correct tracheal tube placement.
It is desirable to provide a light-wand intubation device that enables respiratory gas monitoring during intubation for positive confirmation of correct tracheal tube placement.
It is also desirable to provide a light-wand intubation device that has a holding structure for holding a proximal end portion of a stylet placed in the light-wand in a first mode of operation and for enabling retracting or removing of the stylet from the light-wand in a second mode of operation.
It is also desirable to provide a light-wand intubation device having a light source that: produces substantially less heat than incandescent light; has adjustable light intensity; and, selectively provides white light or visible red light.